BS/EN 352-4-2020 pdf download.Hearing protectors – Safety requirements Part 4 : Level-dependent earmuffs.
This BS/EN 352-4 is applicable to level-dependent earmuffs. It specifies requirements on construction, design, performance, marking and user information related to the inclusion of the level-dependent functionality.
Level-dependent earmuffs are designed to provide restoration of external sounds, while providing attenuation of sounds at high levels. They may be selected for use in intermittent or impulsive noise environments and where external warning sounds are required to be heard. This document is concerned with those earmuffs having an electronic sound restoration circuit.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
EN 352-1:2020, Hearing protectors – General requirements – Part 1: Earmuffs
EN 352-3:2020, Hearing protectors – General requirements – Part 3: Earmuffs attached to head protection and/or face protection devices
EN 13819-3:2019, Hearing protectors — Testing — Part 3: Sup plementaiy acoustic test methods 3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 352-1:2020, EN 352-3:2020 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at http://www.electropedia.orgj
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
level-dependent earmuff
earmuff fitted with an electronic sound restoration circuit
3.2
sound restoration circuit
electroacoustic device intended to reproduce lower level external sounds in the ear canal, and to restrict reproduction of higher level sounds by means of a level-dependent gain function
3.3
criterion level (H)
A-weighted sound pressure level of the H noise for which the A-weighted equivalent diffuse-field related sound pressure level, when a level-dependent earmuff is worn and the sound restoration circuit is operating at maximum volume, first exceeds 85 dB(A)
3.4
criterion level (M)
A-weighted sound pressure level of the M noise for which the A-weighted equivalent diffuse-field
related sound pressure level, when a level-dependent earmuff is worn and the sound restoration circuit
is operating at maximum volume, first exceeds 85 dB(A)
3.5
criterion level (L)
A-weighted sound pressure level of the L noise for which the A-weighted equivalent diffuse-field related
sound pressure level, when a level-dependent earmuff is worn and the sound restoration circuit is
operating at maximum volume, first exceeds 85 dB(A)
3.6
impulse-type noise
noise characterized by short duration high-level peaks
4 Requirements
4.1 General
Level-dependent earmuffs shall meet the requirements of EN 352-1:2020 (or EN 352-3:2020, as appropriate) and the requirements listed in 4.2.
4.2 Performance
4.2.1 Criterion levels
The criterion levels for the three noises H, M and L shall be determined in accordance with test procedures as specified in EN 13819-3:2019, 7.2.2.
4.2.2 Criterion levels for products intended for use in impulse-type noise situations only
Products that are intended for use in impulse-type noise situations only shall meet the requirements:
— minimum criterion level (H) = 85 dB(A);
— minimum criterion level (M) = 85 dB(A);
— minimum criterion level (L) = 85 dB(A).
4.2.3 Criterion levels for products not intended for use In Impulse-type noise situations only
Products that are not intended for use in impulse-type noise situations only shall meet the following requirements:
— minimum criterion level (H) = 97 dB(A);
— minimum criterion level (M) = 96 dB(A);
— minimum criterion level (L) = 94 dB(A).
if there is no difference between the criterion level (L) when the level-dependent function is on and oft,
the requirement minimum criterion level (L) does not apply
5 Marking
The marking specified in EN 352-1:2020 (or EN 352-3:2020, as appropriate) shall be used. No additional marking is needed.
6 Manufacturer’s instructions and information
The information specified in EN 352-1:2020 (or EN 352-3:2020 as appropriate) and the following additional information shall be supplied with the earmuffs:
a) a reference to this document EN 352-4:2020;
b) an indication that the hearing protector provides a level-dependent functionality;
c) the values of the criterion levels as determined by the procedures described In EN 13819-3:2019;
d) a method for checking, charging and changing batteries;
e) statements that include the following information:
1) The earmuff is provided with level-dependent attenuation. The user should check correct operation before use. If distortion or failure is detected, the user should refer to the manufacturer’s advice for maintenance.
2) A warning that the performance may deteriorate with battery usage and the typical period of continuous use that can be expected from the earmuff batteries, when fully charged.
1) in case that the product does not fulfil the criterion requirements in 4.2.3 but fulfils the requirements of 4.2.2 a warning that the product is not suited for high continuous noise levels.BS/EN 352-4-2020 pdf download.

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